Writing instrument



April 15, 1952 J. F. THULL WRITING INSTRUMENT Filed July 10, 1946 INVENTOR JOHN F. THULL.

l I l l I lulllh l. I] nlll Patented Apr. 15, 1952 WRITING INSTRUMENT John F. Thull, Minneapolis, Minn; assignor to- Brown &Bigelow, St. Paul, Minn.

Application July 10, 1946, sesame. 682.712

1 Claim. 1

This invention relates to a ball point pen where the ink reservoir is held within the casing as a unit. The ink unit is replaceable by removing the writing end of the casing and thus releasing the ink unit so that a new, complete unit with the writing ball may be placed in the casing and the writing end replaced in operating posi-- tion.

A feature of primary importance to this writing instrument resides in the manner in which the ink unit and writing ball may be moved into writing position from the concealed position of the ball when the instrument is not in use. To operate the ink unit into writing position it is only necessary to press on the rear end of the same which projects out of the rear end of the casing; and to release the ink unit into inoperative position, in which position the ball is concealed within the forward end of the casing, it is only necessary to again press on the rear end of the casing and ink unit whereupon the catch which holds the unit in writing position is released and a coil spring automatically moves the ink unit into a retracted position.

The ink used in my writing instrument is of a non-drying nature, and the pen does not require a cap to cover the writing ball to seal it from the outer atmosphere like ordinary fountain pens. In my writing instrument where this non-drying, paste-like ink is used, the writing ball may be withdrawn or retracted into the casing so that it will not contact any surface when not in use; and thus I eliminate the necessity of a cap to cover the writing ball.

The features and objects of this invention will be clearly and fully defined throughout the specification and claims.

In the drawings forming part of this specification:

Figure l is a longitudinal section throughout the casing of my writing instrument and showing the ink unit and writing ball in position for writing.

Figure 2 is a longitudinal section similar to Figure 1 showing the ink unit and writing ball retracted into the casing to cover the writing ball when the instrument is not in use.

My writing instrument A is formed with a casing having a forward removable end. The rear end ll of the casing supports a pocket clip I2, and an opening I3 is formed at the extreme rear end.

Within the casing of the pen A, I provide an ink unit B which has a hollow ink chamber I4 and on the forward end of the unit B I mounta 2. ball bearing 15. The ball bearing. l5is$ free to rotate and is adapted to draw the ink from the reservoir M by capillary attraction. An air hole I6 is formed in the tube l4 near the rear end thereof which permits air to be admitted into the chamber of the tube It to replace the used ink and to balance the air pressure in the tube M with atmospheric pressure.

The ink unit B is formed with a rod I! on the rear end thereof in which an annular groove is is positioned within the rear end H of the casing. I provide spring fingers l9 which engage in the groove l8 to hold the writing unit B in operative position, as illustrated in Figure 1. I also provide a finger releasing sleeve 20 which extends around the rod l! and is anchored at 2| in the rear end of the casing I I.

The rear portion H of the casing is slideably mounted on the inner sleeve 22 causing it to slightly telescope and is limited in its movements by the slot 23 in which the lug 24 operates. In the forward end of the casing 10, I provide a coil spring 25 which bears against the unit B and is adapted to urge same in a backward position when the spring fingers i9 are released.

When it is desired to release the spring fingers l9 from the groove is the operator presses on the rear end 26 of the rod l1 and also on the rear end of the casing portion 1 l which slides this portion Il forward so that the sleeve 20 will disengage the fingers [9 from the groove l8; then the operator quickly releases the pressure on the end 26 and on the casing whereupon the spring 25 will automatically force the ink unit B into the retracted position illustrated in Figure 2. In this position illustrated in Figure 2, writing ball I5 is concealed against contact with any surface, and in which position it remains until the operator of the instrument A'wishes to write with the same. The ink unit B with the writing ball may be moved into writing position as illustrated in Figure 1 by pressing upon the end 26 of the rod H whereupon the spring fingers [9 will engage in the annular recess l8 and thus hold the unit B in writing position.

The unit B may be replaced by removing the writing end of the pen which is facilitated by the threads 21.

It is a primary feature to provide a writing.

instrument which is equipped with a replaceable ink unit which unit can be moved either into writing position or retracted into inoperative position by merely pressing on the rear end of the instrument and ink unit.

I claim:

In a writing instrument, a moveable rear oute casing, an inner casing, an ink reservoir unit having a writing end formed thereon and slideable within said inner casing, a rod member secured to the upper end of said unit and projecting from said outer casing and having an annular groove formed therein, spring fingers secured to the inner surface of said inner casing adapted to engage said annular groove to hold said writing end extended from said outer casing, a sleeve secured to the inner surface of said outer casing adapted to force said spring fingers from said annular groove when said outer casing is moved upon said inner casing together with said rod member.

JOHN F. THULL.

REFERENCES CITED The following references are of record in the file of this patent:

Number 15 Number 4 UNITED STATES PATENTS Name Date Gleason July 23, 1901 Heyn Oct. 24, 1916 Harris Nov. 4, 1924 Lloyd July 28, 1925 Henzel Feb. 5, 1929 Maslin July 5, 1938 Gruber Sept. 14, 1948 Heyberger Sept. 21, 1948 Randolph Sept. 13, 1949 Biro Dec. 13, 1949 FOREIGN PATENTS Country Date Germany Apr. 2, 1886 

